<?php  if ( ! defined('BASEPATH')) exit('No direct script access allowed');
/**
 * CodeIgniter
 *
 * An open source application development framework for PHP 4.3.2 or newer
 *
 * @package		CodeIgniter
 * @author		ExpressionEngine Dev Team
 * @copyright	Copyright (c) 2008 - 2009, EllisLab, Inc.
 * @license		http://codeigniter.com/user_guide/license.html
 * @link		http://codeigniter.com
 * @since		Version 1.0
 * @filesource
 */

// ------------------------------------------------------------------------

/**
 * Input Class
 *
 * Pre-processes global input data for security
 *
 * @package		CodeIgniter
 * @subpackage	Libraries
 * @category	Input
 * @author		ExpressionEngine Dev Team
 * @link		http://codeigniter.com/user_guide/libraries/input.html
 */
class CI_Input {
	var $use_xss_clean		= FALSE;
	var $xss_hash			= '';
	var $ip_address			= FALSE;
	var $user_agent			= FALSE;
	var $allow_get_array	= FALSE;

	/* never allowed, string replacement */
	var $never_allowed_str = array(
									'document.cookie'	=> '[removed]',
									'document.write'	=> '[removed]',
									'.parentNode'		=> '[removed]',
									'.innerHTML'		=> '[removed]',
									'window.location'	=> '[removed]',
									'-moz-binding'		=> '[removed]',
									'<!--'				=> '&lt;!--',
									'-->'				=> '--&gt;',
									'<![CDATA['			=> '&lt;![CDATA['
									);
									/* never allowed, regex replacement */
									var $never_allowed_regex = array(
										"javascript\s*:"			=> '[removed]',
										"expression\s*(\(|&\#40;)"	=> '[removed]', // CSS and IE
										"vbscript\s*:"				=> '[removed]', // IE, surprise!
										"Redirect\s+302"			=> '[removed]'
										);

										/**
										 * Constructor
										 *
										 * Sets whether to globally enable the XSS processing
										 * and whether to allow the $_GET array
										 *
										 * @access	public
										 */
										function CI_Input()
										{
											log_message('debug', "Input Class Initialized");

											$CFG =& load_class('Config');
											$this->use_xss_clean	= ($CFG->item('global_xss_filtering') === TRUE) ? TRUE : FALSE;
											$this->allow_get_array	= ($CFG->item('enable_query_strings') === TRUE) ? TRUE : FALSE;
											$this->_sanitize_globals();
										}

										// --------------------------------------------------------------------

										/**
										 * Sanitize Globals
										 *
										 * This function does the following:
										 *
										 * Unsets $_GET data (if query strings are not enabled)
										 *
										 * Unsets all globals if register_globals is enabled
										 *
										 * Standardizes newline characters to \n
										 *
										 * @access	private
										 * @return	void
										 */
										function _sanitize_globals()
										{
											// Would kind of be "wrong" to unset any of these GLOBALS
											$protected = array('_SERVER', '_GET', '_POST', '_FILES', '_REQUEST', '_SESSION', '_ENV', 'GLOBALS', 'HTTP_RAW_POST_DATA',
							'system_folder', 'application_folder', 'BM', 'EXT', 'CFG', 'URI', 'RTR', 'OUT', 'IN');

											// Unset globals for security.
											// This is effectively the same as register_globals = off
											foreach (array($_GET, $_POST, $_COOKIE, $_SERVER, $_FILES, $_ENV, (isset($_SESSION) && is_array($_SESSION)) ? $_SESSION : array()) as $global)
											{
												if ( ! is_array($global))
												{
													if ( ! in_array($global, $protected))
													{
														unset($GLOBALS[$global]);
													}
												}
												else
												{
													foreach ($global as $key => $val)
													{
														if ( ! in_array($key, $protected))
														{
															unset($GLOBALS[$key]);
														}

														if (is_array($val))
														{
															foreach($val as $k => $v)
															{
																if ( ! in_array($k, $protected))
																{
																	unset($GLOBALS[$k]);
																}
															}
														}
													}
												}
											}

											// Is $_GET data allowed? If not we'll set the $_GET to an empty array
											if ($this->allow_get_array == FALSE)
											{
												$_GET = array();
											}
											else
											{
												$_GET = $this->_clean_input_data($_GET);
											}

											// Clean $_POST Data
											$_POST = $this->_clean_input_data($_POST);

											// Clean $_COOKIE Data
											// Also get rid of specially treated cookies that might be set by a server
											// or silly application, that are of no use to a CI application anyway
											// but that when present will trip our 'Disallowed Key Characters' alarm
											// http://www.ietf.org/rfc/rfc2109.txt
											// note that the key names below are single quoted strings, and are not PHP variables
											unset($_COOKIE['$Version']);
											unset($_COOKIE['$Path']);
											unset($_COOKIE['$Domain']);
											$_COOKIE = $this->_clean_input_data($_COOKIE);

											log_message('debug', "Global POST and COOKIE data sanitized");
										}

										// --------------------------------------------------------------------

										/**
										 * Clean Input Data
										 *
										 * This is a helper function. It escapes data and
										 * standardizes newline characters to \n
										 *
										 * @access	private
										 * @param	string
										 * @return	string
										 */
										function _clean_input_data($str)
										{
											if (is_array($str))
											{
												$new_array = array();
												foreach ($str as $key => $val)
												{
													$new_array[$this->_clean_input_keys($key)] = $this->_clean_input_data($val);
												}
												return $new_array;
											}

											// We strip slashes if magic quotes is on to keep things consistent
											if (get_magic_quotes_gpc())
											{
												$str = stripslashes($str);
											}

											// Should we filter the input data?
											if ($this->use_xss_clean === TRUE)
											{
												$str = $this->xss_clean($str);
											}

											// Standardize newlines
											if (strpos($str, "\r") !== FALSE)
											{
												$str = str_replace(array("\r\n", "\r"), "\n", $str);
											}

											return $str;
										}

										// --------------------------------------------------------------------

										/**
										 * Clean Keys
										 *
										 * This is a helper function. To prevent malicious users
										 * from trying to exploit keys we make sure that keys are
										 * only named with alpha-numeric text and a few other items.
										 *
										 * @access	private
										 * @param	string
										 * @return	string
										 */
										function _clean_input_keys($str)
										{
											if ( ! preg_match("/^[a-z0-9:_\/-]+$/i", $str))
											{
												exit('Disallowed Key Characters.');
											}

											return $str;
										}

										// --------------------------------------------------------------------

										/**
										 * Fetch from array
										 *
										 * This is a helper function to retrieve values from global arrays
										 *
										 * @access	private
										 * @param	array
										 * @param	string
										 * @param	bool
										 * @return	string
										 */
										function _fetch_from_array(&$array, $index = '', $xss_clean = FALSE)
										{
											if ( ! isset($array[$index]))
											{
												return FALSE;
											}

											if ($xss_clean === TRUE)
											{
												return $this->xss_clean($array[$index]);
											}

											return $array[$index];
										}

										// --------------------------------------------------------------------

										/**
										 * Fetch an item from the GET array
										 *
										 * @access	public
										 * @param	string
										 * @param	bool
										 * @return	string
										 */
										function get($index = '', $xss_clean = FALSE)
										{
											return $this->_fetch_from_array($_GET, $index, $xss_clean);
										}

										// --------------------------------------------------------------------

										/**
										 * Fetch an item from the POST array
										 *
										 * @access	public
										 * @param	string
										 * @param	bool
										 * @return	string
										 */
										function post($index = '', $xss_clean = FALSE)
										{
											return $this->_fetch_from_array($_POST, $index, $xss_clean);
										}


										function request($index = '', $xss_clean = FALSE){
											return $this->_fetch_from_array($_REQUEST, $index, $xss_clean);
										}

										// --------------------------------------------------------------------

										/**
										 * Fetch an item from either the GET array or the POST
										 *
										 * @access	public
										 * @param	string	The index key
										 * @param	bool	XSS cleaning
										 * @return	string
										 */
										function get_post($index = '', $xss_clean = FALSE)
										{
											if ( ! isset($_POST[$index]) )
											{
												return $this->get($index, $xss_clean);
											}
											else
											{
												return $this->post($index, $xss_clean);
											}
										}

										/**
										 * Le um item do array GET ou POST ou REQUEST
										 *
										 * @access	public
										 * @param	string	The index key
										 * @param	bool	XSS cleaning
										 * @return	string
										 */
										function get_post_request($index = '', $xss_clean = FALSE)
										{
											if (isset($_POST[$index]) )
											{
												return $this->post($index, $xss_clean);
											}
											else if(isset ($_GET[$index]))
											{
												return $this->post($index, $xss_clean);
											}else{
												return $this->request($index, $xss_clean);
											}
										}

										/**
										 * Le um item do array REQUEST ou SESSION
										 *
										 * @access	public
										 * @param	string	The index key
										 * @param	bool	XSS cleaning
										 * @return	string
										 */
										function session_request($index = '', $xss_clean = FALSE)
										{
											if (isset($_SESSION[$index]) )
											{
												return $this->_fetch_from_array($_SESSION, $index, $xss_clean);
											}
											else
											{
												return $this->_fetch_from_array($_REQUEST, $index, $xss_clean);
											}
										}

										// --------------------------------------------------------------------

										/**
										 * Fetch an item from the COOKIE array
										 *
										 * @access	public
										 * @param	string
										 * @param	bool
										 * @return	string
										 */
										function cookie($index = '', $xss_clean = FALSE)
										{
											return $this->_fetch_from_array($_COOKIE, $index, $xss_clean);
										}

										// --------------------------------------------------------------------

										/**
										 * Fetch an item from the SERVER array
										 *
										 * @access	public
										 * @param	string
										 * @param	bool
										 * @return	string
										 */
										function server($index = '', $xss_clean = FALSE)
										{
											return $this->_fetch_from_array($_SERVER, $index, $xss_clean);
										}

										// --------------------------------------------------------------------

										/**
										 * Fetch the IP Address
										 *
										 * @access	public
										 * @return	string
										 */
										function ip_address()
										{
											if ($this->ip_address !== FALSE)
											{
												return $this->ip_address;
											}

											if (config_item('proxy_ips') != '' && $this->server('HTTP_X_FORWARDED_FOR') && $this->server('REMOTE_ADDR'))
											{
												$proxies = preg_split('/[\s,]/', config_item('proxy_ips'), -1, PREG_SPLIT_NO_EMPTY);
												$proxies = is_array($proxies) ? $proxies : array($proxies);

												$this->ip_address = in_array($_SERVER['REMOTE_ADDR'], $proxies) ? $_SERVER['HTTP_X_FORWARDED_FOR'] : $_SERVER['REMOTE_ADDR'];
											}
											elseif ($this->server('REMOTE_ADDR') AND $this->server('HTTP_CLIENT_IP'))
											{
												$this->ip_address = $_SERVER['HTTP_CLIENT_IP'];
											}
											elseif ($this->server('REMOTE_ADDR'))
											{
												$this->ip_address = $_SERVER['REMOTE_ADDR'];
											}
											elseif ($this->server('HTTP_CLIENT_IP'))
											{
												$this->ip_address = $_SERVER['HTTP_CLIENT_IP'];
											}
											elseif ($this->server('HTTP_X_FORWARDED_FOR'))
											{
												$this->ip_address = $_SERVER['HTTP_X_FORWARDED_FOR'];
											}

											if ($this->ip_address === FALSE)
											{
												$this->ip_address = '0.0.0.0';
												return $this->ip_address;
											}

											if (strstr($this->ip_address, ','))
											{
												$x = explode(',', $this->ip_address);
												$this->ip_address = trim(end($x));
											}

											if ( ! $this->valid_ip($this->ip_address))
											{
												$this->ip_address = '0.0.0.0';
											}

											return $this->ip_address;
										}

										// --------------------------------------------------------------------

										/**
										 * Validate IP Address
										 *
										 * Updated version suggested by Geert De Deckere
										 *
										 * @access	public
										 * @param	string
										 * @return	string
										 */
										function valid_ip($ip)
										{
											$ip_segments = explode('.', $ip);

											// Always 4 segments needed
											if (count($ip_segments) != 4)
											{
												return FALSE;
											}
											// IP can not start with 0
											if ($ip_segments[0][0] == '0')
											{
												return FALSE;
											}
											// Check each segment
											foreach ($ip_segments as $segment)
											{
												// IP segments must be digits and can not be
												// longer than 3 digits or greater then 255
												if ($segment == '' OR preg_match("/[^0-9]/", $segment) OR $segment > 255 OR strlen($segment) > 3)
												{
													return FALSE;
												}
											}

											return TRUE;
										}

										// --------------------------------------------------------------------

										/**
										 * User Agent
										 *
										 * @access	public
										 * @return	string
										 */
										function user_agent()
										{
											if ($this->user_agent !== FALSE)
											{
												return $this->user_agent;
											}

											$this->user_agent = ( ! isset($_SERVER['HTTP_USER_AGENT'])) ? FALSE : $_SERVER['HTTP_USER_AGENT'];

											return $this->user_agent;
										}

										// --------------------------------------------------------------------

										/**
										 * Filename Security
										 *
										 * @access	public
										 * @param	string
										 * @return	string
										 */
										function filename_security($str)
										{
											$bad = array(
						"../",
						"./",
						"<!--",
						"-->",
						"<",
						">",
						"'",
						'"',
						'&',
						'$',
						'#',
						'{',
						'}',
						'[',
						']',
						'=',
						';',
						'?',
						"%20",
						"%22",
						"%3c",		// <
						"%253c", 	// <
						"%3e", 		// >
						"%0e", 		// >
						"%28", 		// (  
						"%29", 		// ) 
						"%2528", 	// (
						"%26", 		// &
						"%24", 		// $
						"%3f", 		// ?
						"%3b", 		// ;
						"%3d"		// =
											);

											return stripslashes(str_replace($bad, '', $str));
										}

										// --------------------------------------------------------------------

										/**
										 * XSS Clean
										 *
										 * Sanitizes data so that Cross Site Scripting Hacks can be
										 * prevented.  This function does a fair amount of work but
										 * it is extremely thorough, designed to prevent even the
										 * most obscure XSS attempts.  Nothing is ever 100% foolproof,
										 * of course, but I haven't been able to get anything passed
										 * the filter.
										 *
										 * Note: This function should only be used to deal with data
										 * upon submission.  It's not something that should
										 * be used for general runtime processing.
										 *
										 * This function was based in part on some code and ideas I
										 * got from Bitflux: http://blog.bitflux.ch/wiki/XSS_Prevention
										 *
										 * To help develop this script I used this great list of
										 * vulnerabilities along with a few other hacks I've
										 * harvested from examining vulnerabilities in other programs:
										 * http://ha.ckers.org/xss.html
										 *
										 * @access	public
										 * @param	string
										 * @return	string
										 */
										function xss_clean($str, $is_image = FALSE)
										{
											/*
											 * Is the string an array?
											 *
											 */
											if (is_array($str))
											{
												while (list($key) = each($str))
												{
													$str[$key] = $this->xss_clean($str[$key]);
												}

												return $str;
											}

											/*
											 * Remove Invisible Characters
											 */
											$str = $this->_remove_invisible_characters($str);

											/*
											 * Protect GET variables in URLs
											 */

											// 901119URL5918AMP18930PROTECT8198

											$str = preg_replace('|\&([a-z\_0-9]+)\=([a-z\_0-9]+)|i', $this->xss_hash()."\\1=\\2", $str);

											/*
											 * Validate standard character entities
											 *
											 * Add a semicolon if missing.  We do this to enable
											 * the conversion of entities to ASCII later.
											 *
											 */
											$str = preg_replace('#(&\#?[0-9a-z]{2,})([\x00-\x20])*;?#i', "\\1;\\2", $str);

											/*
											 * Validate UTF16 two byte encoding (x00)
											 *
											 * Just as above, adds a semicolon if missing.
											 *
											 */
											$str = preg_replace('#(&\#x?)([0-9A-F]+);?#i',"\\1\\2;",$str);

											/*
											 * Un-Protect GET variables in URLs
											 */
											$str = str_replace($this->xss_hash(), '&', $str);

											/*
											 * URL Decode
											 *
											 * Just in case stuff like this is submitted:
											 *
											 * <a href="http://%77%77%77%2E%67%6F%6F%67%6C%65%2E%63%6F%6D">Google</a>
											 *
											 * Note: Use rawurldecode() so it does not remove plus signs
											 *
											 */
											$str = rawurldecode($str);

											/*
											 * Convert character entities to ASCII
											 *
											 * This permits our tests below to work reliably.
											 * We only convert entities that are within tags since
											 * these are the ones that will pose security problems.
											 *
											 */

											$str = preg_replace_callback("/[a-z]+=([\'\"]).*?\\1/si", array($this, '_convert_attribute'), $str);

											$str = preg_replace_callback("/<\w+.*?(?=>|<|$)/si", array($this, '_html_entity_decode_callback'), $str);

											/*
											 * Remove Invisible Characters Again!
											 */
											$str = $this->_remove_invisible_characters($str);

											/*
											 * Convert all tabs to spaces
											 *
											 * This prevents strings like this: ja	vascript
											 * NOTE: we deal with spaces between characters later.
											 * NOTE: preg_replace was found to be amazingly slow here on large blocks of data,
											 * so we use str_replace.
											 *
											 */

											if (strpos($str, "\t") !== FALSE)
											{
												$str = str_replace("\t", ' ', $str);
											}

											/*
											 * Capture converted string for later comparison
											 */
											$converted_string = $str;

											/*
											 * Not Allowed Under Any Conditions
											 */

											foreach ($this->never_allowed_str as $key => $val)
											{
												$str = str_replace($key, $val, $str);
											}

											foreach ($this->never_allowed_regex as $key => $val)
											{
												$str = preg_replace("#".$key."#i", $val, $str);
											}

											/*
											 * Makes PHP tags safe
											 *
											 *  Note: XML tags are inadvertently replaced too:
											 *
											 *	<?xml
											 *
											 * But it doesn't seem to pose a problem.
											 *
											 */
											if ($is_image === TRUE)
											{
												// Images have a tendency to have the PHP short opening and closing tags every so often
												// so we skip those and only do the long opening tags.
												$str = preg_replace('/<\?(php)/i', "&lt;?\\1", $str);
											}
											else
											{
												$str = str_replace(array('<?', '?'.'>'),  array('&lt;?', '?&gt;'), $str);
											}

											/*
											 * Compact any exploded words
											 *
											 * This corrects words like:  j a v a s c r i p t
											 * These words are compacted back to their correct state.
											 *
											 */
											$words = array('javascript', 'expression', 'vbscript', 'script', 'applet', 'alert', 'document', 'write', 'cookie', 'window');
											foreach ($words as $word)
											{
												$temp = '';

												for ($i = 0, $wordlen = strlen($word); $i < $wordlen; $i++)
												{
													$temp .= substr($word, $i, 1)."\s*";
												}

												// We only want to do this when it is followed by a non-word character
												// That way valid stuff like "dealer to" does not become "dealerto"
												$str = preg_replace_callback('#('.substr($temp, 0, -3).')(\W)#is', array($this, '_compact_exploded_words'), $str);
											}

											/*
											 * Remove disallowed Javascript in links or img tags
											 * We used to do some version comparisons and use of stripos for PHP5, but it is dog slow compared
											 * to these simplified non-capturing preg_match(), especially if the pattern exists in the string
											 */
											do
											{
												$original = $str;

												if (preg_match("/<a/i", $str))
												{
													$str = preg_replace_callback("#<a\s+([^>]*?)(>|$)#si", array($this, '_js_link_removal'), $str);
												}

												if (preg_match("/<img/i", $str))
												{
													$str = preg_replace_callback("#<img\s+([^>]*?)(\s?/?>|$)#si", array($this, '_js_img_removal'), $str);
												}

												if (preg_match("/script/i", $str) OR preg_match("/xss/i", $str))
												{
													$str = preg_replace("#<(/*)(script|xss)(.*?)\>#si", '[removed]', $str);
												}
											}
											while($original != $str);

											unset($original);

											/*
											 * Remove JavaScript Event Handlers
											 *
											 * Note: This code is a little blunt.  It removes
											 * the event handler and anything up to the closing >,
											 * but it's unlikely to be a problem.
											 *
											 */
											$event_handlers = array('[^a-z_\-]on\w*','xmlns');

											if ($is_image === TRUE)
											{
												/*
												 * Adobe Photoshop puts XML metadata into JFIF images, including namespacing,
												 * so we have to allow this for images. -Paul
												 */
												unset($event_handlers[array_search('xmlns', $event_handlers)]);
											}

											$str = preg_replace("#<([^><]+?)(".implode('|', $event_handlers).")(\s*=\s*[^><]*)([><]*)#i", "<\\1\\4", $str);

											/*
											 * Sanitize naughty HTML elements
											 *
											 * If a tag containing any of the words in the list
											 * below is found, the tag gets converted to entities.
											 *
											 * So this: <blink>
											 * Becomes: &lt;blink&gt;
											 *
											 */
											$naughty = 'alert|applet|audio|basefont|base|behavior|bgsound|blink|body|embed|expression|form|frameset|frame|head|html|ilayer|iframe|input|isindex|layer|link|meta|object|plaintext|style|script|textarea|title|video|xml|xss';
											$str = preg_replace_callback('#<(/*\s*)('.$naughty.')([^><]*)([><]*)#is', array($this, '_sanitize_naughty_html'), $str);

											/*
											 * Sanitize naughty scripting elements
											 *
											 * Similar to above, only instead of looking for
											 * tags it looks for PHP and JavaScript commands
											 * that are disallowed.  Rather than removing the
											 * code, it simply converts the parenthesis to entities
											 * rendering the code un-executable.
											 *
											 * For example:	eval('some code')
											 * Becomes:		eval&#40;'some code'&#41;
											 *
											 */
											$str = preg_replace('#(alert|cmd|passthru|eval|exec|expression|system|fopen|fsockopen|file|file_get_contents|readfile|unlink)(\s*)\((.*?)\)#si', "\\1\\2&#40;\\3&#41;", $str);

											/*
											 * Final clean up
											 *
											 * This adds a bit of extra precaution in case
											 * something got through the above filters
											 *
											 */
											foreach ($this->never_allowed_str as $key => $val)
											{
												$str = str_replace($key, $val, $str);
											}

											foreach ($this->never_allowed_regex as $key => $val)
											{
												$str = preg_replace("#".$key."#i", $val, $str);
											}

											/*
											 *  Images are Handled in a Special Way
											 *  - Essentially, we want to know that after all of the character conversion is done whether
											 *  any unwanted, likely XSS, code was found.  If not, we return TRUE, as the image is clean.
											 *  However, if the string post-conversion does not matched the string post-removal of XSS,
											 *  then it fails, as there was unwanted XSS code found and removed/changed during processing.
											 */

											if ($is_image === TRUE)
											{
												if ($str == $converted_string)
												{
													return TRUE;
												}
												else
												{
													return FALSE;
												}
											}

											log_message('debug', "XSS Filtering completed");
											return $str;
										}

										// --------------------------------------------------------------------

										/**
										 * Random Hash for protecting URLs
										 *
										 * @access	public
										 * @return	string
										 */
										function xss_hash()
										{
											if ($this->xss_hash == '')
											{
												if (phpversion() >= 4.2)
												mt_srand();
												else
												mt_srand(hexdec(substr(md5(microtime()), -8)) & 0x7fffffff);

												$this->xss_hash = md5(time() + mt_rand(0, 1999999999));
											}

											return $this->xss_hash;
										}

										// --------------------------------------------------------------------

										/**
										 * Remove Invisible Characters
										 *
										 * This prevents sandwiching null characters
										 * between ascii characters, like Java\0script.
										 *
										 * @access	public
										 * @param	string
										 * @return	string
										 */
										function _remove_invisible_characters($str)
										{
											static $non_displayables;

											if ( ! isset($non_displayables))
											{
												// every control character except newline (dec 10), carriage return (dec 13), and horizontal tab (dec 09),
												$non_displayables = array(
										'/%0[0-8bcef]/',			// url encoded 00-08, 11, 12, 14, 15
										'/%1[0-9a-f]/',				// url encoded 16-31
										'/[\x00-\x08]/',			// 00-08
										'/\x0b/', '/\x0c/',			// 11, 12
										'/[\x0e-\x1f]/'				// 14-31
												);
											}

											do
											{
												$cleaned = $str;
												$str = preg_replace($non_displayables, '', $str);
											}
											while ($cleaned != $str);

											return $str;
										}

										// --------------------------------------------------------------------

										/**
										 * Compact Exploded Words
										 *
										 * Callback function for xss_clean() to remove whitespace from
										 * things like j a v a s c r i p t
										 *
										 * @access	public
										 * @param	type
										 * @return	type
										 */
										function _compact_exploded_words($matches)
										{
											return preg_replace('/\s+/s', '', $matches[1]).$matches[2];
										}

										// --------------------------------------------------------------------

										/**
										 * Sanitize Naughty HTML
										 *
										 * Callback function for xss_clean() to remove naughty HTML elements
										 *
										 * @access	private
										 * @param	array
										 * @return	string
										 */
										function _sanitize_naughty_html($matches)
										{
											// encode opening brace
											$str = '&lt;'.$matches[1].$matches[2].$matches[3];

											// encode captured opening or closing brace to prevent recursive vectors
											$str .= str_replace(array('>', '<'), array('&gt;', '&lt;'), $matches[4]);

											return $str;
										}

										// --------------------------------------------------------------------

										/**
										 * JS Link Removal
										 *
										 * Callback function for xss_clean() to sanitize links
										 * This limits the PCRE backtracks, making it more performance friendly
										 * and prevents PREG_BACKTRACK_LIMIT_ERROR from being triggered in
										 * PHP 5.2+ on link-heavy strings
										 *
										 * @access	private
										 * @param	array
										 * @return	string
										 */
										function _js_link_removal($match)
										{
											$attributes = $this->_filter_attributes(str_replace(array('<', '>'), '', $match[1]));
											return str_replace($match[1], preg_replace("#href=.*?(alert\(|alert&\#40;|javascript\:|charset\=|window\.|document\.|\.cookie|<script|<xss|base64\s*,)#si", "", $attributes), $match[0]);
										}

										/**
										 * JS Image Removal
										 *
										 * Callback function for xss_clean() to sanitize image tags
										 * This limits the PCRE backtracks, making it more performance friendly
										 * and prevents PREG_BACKTRACK_LIMIT_ERROR from being triggered in
										 * PHP 5.2+ on image tag heavy strings
										 *
										 * @access	private
										 * @param	array
										 * @return	string
										 */
										function _js_img_removal($match)
										{
											$attributes = $this->_filter_attributes(str_replace(array('<', '>'), '', $match[1]));
											return str_replace($match[1], preg_replace("#src=.*?(alert\(|alert&\#40;|javascript\:|charset\=|window\.|document\.|\.cookie|<script|<xss|base64\s*,)#si", "", $attributes), $match[0]);
										}

										// --------------------------------------------------------------------

										/**
										 * Attribute Conversion
										 *
										 * Used as a callback for XSS Clean
										 *
										 * @access	public
										 * @param	array
										 * @return	string
										 */
										function _convert_attribute($match)
										{
											return str_replace(array('>', '<', '\\'), array('&gt;', '&lt;', '\\\\'), $match[0]);
										}

										// --------------------------------------------------------------------

										/**
										 * HTML Entity Decode Callback
										 *
										 * Used as a callback for XSS Clean
										 *
										 * @access	public
										 * @param	array
										 * @return	string
										 */
										function _html_entity_decode_callback($match)
										{
											$CFG =& load_class('Config');
											$charset = $CFG->item('charset');

											return $this->_html_entity_decode($match[0], strtoupper($charset));
										}

										// --------------------------------------------------------------------

										/**
										 * HTML Entities Decode
										 *
										 * This function is a replacement for html_entity_decode()
										 *
										 * In some versions of PHP the native function does not work
										 * when UTF-8 is the specified character set, so this gives us
										 * a work-around.  More info here:
										 * http://bugs.php.net/bug.php?id=25670
										 *
										 * @access	private
										 * @param	string
										 * @param	string
										 * @return	string
										 */
										/* -------------------------------------------------
										 /*  Replacement for html_entity_decode()
										 /* -------------------------------------------------*/

										/*
										 NOTE: html_entity_decode() has a bug in some PHP versions when UTF-8 is the
										 character set, and the PHP developers said they were not back porting the
										 fix to versions other than PHP 5.x.
										 */
										function _html_entity_decode($str, $charset='UTF-8')
										{
											if (stristr($str, '&') === FALSE) return $str;

											// The reason we are not using html_entity_decode() by itself is because
											// while it is not technically correct to leave out the semicolon
											// at the end of an entity most browsers will still interpret the entity
											// correctly.  html_entity_decode() does not convert entities without
											// semicolons, so we are left with our own little solution here. Bummer.

											if (function_exists('html_entity_decode') && (strtolower($charset) != 'utf-8' OR version_compare(phpversion(), '5.0.0', '>=')))
											{
												$str = html_entity_decode($str, ENT_COMPAT, $charset);
												$str = preg_replace('~&#x(0*[0-9a-f]{2,5})~ei', 'chr(hexdec("\\1"))', $str);
												return preg_replace('~&#([0-9]{2,4})~e', 'chr(\\1)', $str);
											}

											// Numeric Entities
											$str = preg_replace('~&#x(0*[0-9a-f]{2,5});{0,1}~ei', 'chr(hexdec("\\1"))', $str);
											$str = preg_replace('~&#([0-9]{2,4});{0,1}~e', 'chr(\\1)', $str);

											// Literal Entities - Slightly slow so we do another check
											if (stristr($str, '&') === FALSE)
											{
												$str = strtr($str, array_flip(get_html_translation_table(HTML_ENTITIES)));
											}

											return $str;
										}

										// --------------------------------------------------------------------

										/**
										 * Filter Attributes
										 *
										 * Filters tag attributes for consistency and safety
										 *
										 * @access	public
										 * @param	string
										 * @return	string
										 */
										function _filter_attributes($str)
										{
											$out = '';

											if (preg_match_all('#\s*[a-z\-]+\s*=\s*(\042|\047)([^\\1]*?)\\1#is', $str, $matches))
											{
												foreach ($matches[0] as $match)
												{
													$out .= preg_replace("#/\*.*?\*/#s", '', $match);
												}
											}

											return $out;
										}

										// --------------------------------------------------------------------

}
// END Input class

/* End of file Input.php */
/* Location: ./system/libraries/Input.php */